A Ground Fault Circuit Interrupter (GFCI) is a safety device designed to protect people from electric shock. It works by monitoring the flow of electricity in a circuit. If it detects an imbalance, such as when electricity is leaking to the ground, it quickly shuts off the power to prevent injury. GFCIs are commonly installed in areas where water is present, like bathrooms and kitchens, because moisture increases the risk of electric shock. They can be found in outlets or as part of circuit breakers in the electrical panel. Regular testing of GFCIs is recommended to ensure they function properly.